These rings might look like colorful, interstellar rainbows, but for astronomers they’ve helped solve a mystery.

By studying these rings, which were captured using NASA’s Chandra X-ray Observatory, astronomers were able to determine how far Circinus X-1, a double star system in the plane of our galaxy, is from Earth.

“It’s really hard to get accurate distance measurements in astronomy and we only have a handful of methods,” says Sebastian Heinz of the University of Wisconsin in Madison, who led the study. “But just as bats use sonar to triangulate their location, we can use the X-rays from Circinus X-1 to figure out exactly where it is.”

The rings are “echoes from a burst of X-rays emitted by Circinus X-1 in late 2013,” the space agency said in a statement. “The burst reflected off intervening clouds of dust, with some reflected X-rays arriving to Earth from different angles at…